NE DAY some 50,000 years ago,
along Canon Diablo in northern
Arizona, antelope grazed on a
sagebrush flat near a juniper
woodland. Save for an occasional
saber-toothed tiger and mam
moth, no danger threatened. Man had not
yet appeared on the continent.
Far to the southeast a dazzling glow sud
denly lit the sky. It approached with un
earthly speed, becoming brighter than the
sun and leaving a luminous trail. Every ani
mal lifted its head in alarm.
Without a warning sound the terrible bril
liance was upon them. The very earth ex
ploded. Millions of tons of rock jetted
upward in a great conical sheet. A mon
strous shock wave leveled trees for miles in
every direction. Wildfires burst out sponta
neously, blazing from land already seared
by the giant fireball.
Darkness settled over the area, for pulver
ized rock, dust, and soot, thrown far into
the stratosphere, blocked the sun. Then, as
wind and rain dispersed the veil, the first
feeble light revealed a landscape of desola
tion. Where the fireball had ended its deadly
flight, a high rim encircled a wound in the
earth 4,000 feet across and 750 feet deep.
Thus was born Meteor Crater.
An imaginary scenario? Not at all. Scien
tists in recent years have vastly increased
their understanding of the extraterrestrial
visitors we call meteorites and the craters
they can make. We know that the fireball
thousands of years ago was caused by a
giant chunk of iron and nickel, the Cafion
Diablo meteorite. Air in front of this intrud
er from space became shock-compressed
and highly incandescent. That in turn heat
ed a thin outer layer of the iron body to in
candescence, and molten material streamed
Scar from a cosmic bomb, Arizona's
Meteor Crateris earth's most studied
impact structure.Nearly a mile across
and originally 750 feet deep, the crater
here crusted by snow-is attributedto a
300,000-ton meteorite some 50,000 years
ago. Meteorites of this size, which can
unleash the explosive energy of nuclear
weapons, probably fall less than once
every thousand years. Apparent crater
at left is a bulldozed livestock pond.
National Geographic, September 1986
392